The UK and Scottish governments have been asked to arrange urgent talks to protect the future of Scotland’s only remaining oil refinery at Grangemouth.

Daniel Johnson, Scottish Labour’s economy spokesperson, has written to PetroChina, part of the joint venture that owns the site, seeking to discuss the future of the complex where oil refining is due to cease next year.

He is also urging the Scottish and Westminster governments to arrange meetings.

Petroineos has said it is preparing to shut the Grangemouth facility, where refining has taken place since 1919, to convert it into a fuels import terminal.

Petroineos, a joint venture formed in 2011 between PetroChina, the state-owned Chinese oil company, and Ineos, which is controlled by billionaire Sir Jim Ratcliffe, will operate the complex as normal until at least spring 2025. After that it would operate as an import oil terminal facility only, prompting concerns for the future of 500 jobs.

Grangemouth, on the Forth estuary, is one of six remaining oil refineries in Britain and supplies much of the petrol and diesel for forecourts in Scotland and the north of England.

“Grangemouth is one of Scotland’s key strategic assets, but neither of Scotland’s governments seems to be serious about protecting its future. Both of our governments must get round the table to discuss both urgent action and a real long-term plan to keep Grangemouth working,” Johnson said in a statement.

He said that Labour’s green economy plans would aim to make the Grangemouth site “home to the industries of the future” by setting up a decarbonisation hub and a linked carbon capture and storage project.

Johnson added that he wanted to know why oil refining was still likely to stop by 2025 when the most recent accounts from Petroineos show the site is profitable, and that it has now secured critical investment in the hydrocracker.

Unite, the trade union, is among groups talking with Petroineos to explore ways to extend the lifespan of the oil refinery’s operations, and to develop alternative energy sources at the complex.

Gillian Martin, the minister for energy, just transition and fair work, told the Scottish parliament last week that she had met Petroineos in March and the Scottish government continued to work with the company. She said the Scottish government was examining whether or not Grangemouth could become a biorefinery.

It said: “The Grangemouth site and its workforce are crucial to Scotland’s economy and our transition to net zero.

“The Scottish government is committed to working collaboratively with Petroineos, UK ministers and Unite the union to explore the options available to accelerate new employment opportunities.”

A Department for Energy Security and Net Zero spokesperson said: “This is a commercial decision for the refinery owners, Petroineos. However, we know this is a concerning time for workers and their families, and are working closely with Grangemouth refinery on the long-term future of the site and how they are supporting staff.”

Petroineos said: “We will continue to engage with all relevant stakeholders as we prepare for a transition at the Grangemouth refinery.”